American Falls Reservoir, Power, Bingham, and Bannock cos., SE Idaho, on Snake R. at town of American Falls; 21 mi/34 km long, max. width 9 mi/14.5 km; 42°47'N 112°51'W. Max. capacity 1.7 million acre-ft. Formed by Amer. Falls Dam (89 ft/27 m. high, 5,227 ft/1,593 m long), built (1927) as unit in Minidoka Project for power generation. Town relocated to higher ground with construction of dam. Bounded NE by Fort Hall Indian Reservation.
